In computer analyses that track the evolution of 58 documented folktales, anthropologist Jamshid Tehrani of Durham University in England finds that related versions of “Little Red Riding Hood” spread from a European origin over at least the last millennium.

To illuminate the tale’s history, Tehrani relied on three statistical programs that construct evolutionary family trees, or phylogenies, of people and other organisms based on genetic relationships among living and ancient individuals. Controversial attempts to reconstruct language evolution with phylogenetic methods have also recently appeared (SN: 11/19/11, p. 22).

“The approach I used promises new insights into the origins and relationships of storytelling traditions around the world,” Tehrani says. Folklorists have long struggled to determine whether similar folktales from different parts of the world represent stories or oral traditions that developed independently of one another.

Consider the variety of folktales in Europe and West Africa sometimes thought to be offshoots of “Little Red Riding Hood.” The new results indicate that these tales instead represent variants of “The Wolf and the Kids,” a story popular today in Europe and the Middle East, Tehrani reports November 13 in PLOS ONE.

In “The Wolf and the Kids,” a wolf tricks a goat’s kids into letting him into their house by pretending to be their mother. He then eats the youngsters.

East Asian folktales known collectively as “The Tiger Grandmother” blend elements of “Little Red Riding Hood” and “The Wolf and the Kids,” Tehrani concludes. In these stories, a group of sisters spends the night in bed with a tiger or another predator that has disguised itself as their grandmother. The tiger eats the youngest girl, but the other children trick the villain into letting them escape.

Although some folklorists have suggested that “The Tiger Grandmother” morphed into “Little Red Riding Hood” and “The Wolf and the Kids,” Tehrani proposes that versions of the latter two folktales instead moved from west to east. In his analysis, between around 800 and 600 years ago, “The Tiger Grandmother” emerged as a hybrid of the two western folktales.

Tehrani selected folktales from an international index that categorizes these stories into more than 2,000 types. He calculated relationships among tales based on 72 plot elements, including whether the protagonist is one child or a group of siblings and what type of trick the villain uses to deceive victims.

All three programs identified a distinctive group of European folktales consisting of “Little Red Riding Hood” and two other oral traditions that presumably derived from a common ancestral story. One tale involves a hoodless girl who outwits a wolf before he can eat her. In the other story, a girl deceives an aunt or uncle who is actually a witch or werewolf; the villain then comes to her house and devours her in bed.

Hundreds of slightly different versions of folktales such as “Little Red Riding Hood” exist, apart from the famous Brothers Grimm collections. “Phylogenetic methods bring the rigor of modern statistical tools from biology to untangle the complex histories of these tales,” says psychologist Quentin Atkinson of the University of Auckland in New Zealand. Atkinson and his colleagues have used phylogenetics to identify where versions of another folktale, “The Kind and Unkind Girls,” have clustered over time in Europe.

But some researchers take issue with Tehrani’s methods. Data on folktales are too limited and uncertain to support evolutionary reconstructions, remarks folklorist Timothy Tangherlini of the University of California, Los Angeles. Tehrani analyzed a small set of folktales, Tangherlini says, many of which come from edited or translated collections that don’t accurately represent how tales were originally told.

What’s more, he adds, Tehrani studied story elements that, like others traditionally employed by folklorists, may not apply across diverse languages, cultures and time periods.

Tangherlini and his colleagues are using a statistical method to categorize — but not to create an evolutionary tree for — 35,000 Danish folktales collected a century ago.

Folklorists primarily study how, when and why certain types of tales catch on with storytellers and their audiences, explains folklorist Regina Bendix of the University of Göttingen in Germany. Tehrani’s analysis is not only unreliable, Bendix says, “it does not answer the question ‘What made “Little Red Riding Hood” entertaining enough to keep telling, printing, enacting, singing, parodying and filming across different societies over more than 1,000 years?’”